Single impression multicolor printing



Jan. 7, 1969 J. E. SMITH 3,420,170

SINGLE IMFRESSION MULTICOLOR PRINTING Filed Oct. 11, 1966 Sheet of 4 sam qwu ATTORNEY Jan. 7, 1969 J. E. SMITH 3,420,170

SINGLE IMPRESSION MULTICOLOR PRINTING Filed Oct. 11, 1966 Sheet 2 of 4Jan. 7, 1969 .1. E. SMITH SINGLE IMPRESSION MULTICOLOR PRINTING SheetFiled Oct. 11, 1966 Jan. 7, 1969 J. E. SMITH SINGLE IMPRESSIONMULTICOLOR PRINTING Sheet Filed Oct. 11, 1966 United States PatentOfiice 3,420,170 Patented Jan. 7, 1969 SINGLE IMPRESSION MULTICOLORPRINTING James E. Smith, Avon, Conn., assignor to United AircraftCorporation, Hartford, Conn., a corporation of Delaware Filed Oct. 11,1966, Scr. No. 585,920

US. Cl. 101175 17 Claims Int. Cl. B41f 5/18 This invent-ion relates ingeneral to the art of color printing and, more particularly, to thoseprinting processes wherein multicolor reproductions are effected in asingle impression in high speed presses.

Despite extensive developmental efforts in the field, the printing offull color reproductions on high speed presses, such as those used bythe large daily newspapers, remains a tedious, expensive and relativelyinexact process. Such reproductions are still usually made through theuse of multiple impressions of single colors in successive passes of thepaper or other material to be printed past the individual single-colorprinting plates. Separate plates are prepared, one for each color to beapplied, and successive separate impressions are made on the paper witheach plate, one color imprint being superimposed over the other withappropriate registration to provide the full color illusion in thefinished product.

In order to achieve high quality reproduction in this manner, extremecare is necessary in the preparation of the plates to assure properregistration of the various colors, as well as with the alignment of theplates and with the sequencing operations in the presses. Achieving goodinitial registration of the various color patterns, at very high pressspeeds and under the usual adverse environmental and schedule conditionsprevailing, is usually a substantial task in itself. Even thoughadvances in the field permit a fairly precise alignment of the colorpatterns, to within 0.001 inch in some cases, the requisite registrationis so sensitive that changes occurring during the press run, such asshrinkage or expansion of the paper due to changes in humidity, forexample, readily lead to discernible changes in registration, eventhough the initial alignment was accurate.

Furthermore, the necessity for the close control of ink viscosities anddrying rates imposes additional limitations on the system, particularlywhere one primary color is to be overlaid over another in the printingsequence. In some processes, two or more primary colors are blended toachieve a desired intermediate hue, the initially deposited ink beingphysically mixed or blended with that subsequently overlaid thereon. Inthis type process, the first ink must remain sufiiciently fluid to admixfreely with the ink of the second color when the second impression ismade.

In other inking processes, an optical blending technique is used, thesecond color being laid over the first only after the first depositedink has dried. In some cases, the second color partially bleeds into thefirst with a resultant nonuniformity of print rather than the crispcolor pattern intended. In any event, the press speeds and sequencingmust be coordinated with the ink compositions, compatabilities anddrying rates in order to attain satisfactory results.

The use of full color techniques compatible with the usual black andwhite printing processes, or run-of-thepaper color, would, of course, bea tremendous boon to the large daily newspapers which generally find itnecessary to compete with the other advertising media primarily on theirblack and white capabilities. What is obviously still needed in theindustry is a color printing systern which will produce clear andfaithful full color reproductions by means and at speeds compatible withthe normal newspaper press runs, and which is economically justifiablein view of the nature of the newspaper business.

It is a primary object of the present invention to provide apparatus andmethods for single impression multi-color printing in perfectregistration in high speed presses.

A further object is to provide means efiecting full color registrationin a simple and economical manner.

A still further object is to provide means for reducing the cost ofprinting plate preparation, the production of a single printing platefor each new picture in color replacing the usual multiple platescurrently utilized in these processes.

An additional object is the provision of a printing system wherein theadjustment of just a single variable is necessary to effect and maintaina precise alignment of the ink transfer rollers and with the printingplates.

1 Still another feature of the instant invention is the provision ofapparatus and methods for color printing in which the necessity forprecise rotational alignment of the ink transfer rollers is eliminated,the only alignment necessary being an axial coordination of the rollerswith the printing plate.

An additional feature is the provision of a printing system wherein theintelligence provided on the printing plate comprises interadjacentprojections arranged in triangular array for high color saturation ofthe paper.

A still additional feature is to provide a color printing system whereinno mixing of ink or overlay of one color impression upon another isrequired to achieve optical blending to provide the intermediate hues.

These and other objects and advantages of the present invention will bedescribed in the detailed description which follows or will be evidenttherefrom or from practice of the invention.

When referring to the present printing system in detail, it will beconvenient from time to time to make reference to the attached drawingsof which:

FIG. 1 is a somewhat schematic view of the general arrangement of theoverall printing and inking system, the view being taken in a planeperpendicular to the axis of the various cylinders arranged in parallelin a rotary press.

FIG. 2 is a fragmentary top view, partially in crosssection, of theinking system taken in a plane parallel to the longitudinal axis of thecylinders.

FIG. 3 is a top view of the ink transfer cylinders, illustratingparticularly the alignment of the circumferential ribs provided thereon,which is a preferred construction as described hereinafter.

FIG. 4 is a fragmentary view of the projection array as provided On atypical printing plate, illustrating particularly the triangulararrangement, projection interlacing, and ink striping.

FIG. 5 illustrates the results of conventional inking of a close-packedinterlaced array, such as that shown in FIG. 4.

FIG. 6 illustrates the projection separation necessary in the prior artmethods.

FIG. 7 shows the finished impression made by a single projection onsomewhat absorptive paper, such as newsprint.

FIG. 8 demonstrates the high color saturation attainable with theinterlaced triangular projection pattern on newsprint.

FIGS. 9 and 10 illustrate the extent of color saturation attainable withthe spaced triangular array (FIG. 9) and closed-packed square array(FIG. 10).

It is readily observable that the principal problem in run-'of-the-papercolor stems from the necessity of employing separate printing plates foreach color to be applied, since both the material and labor costs andthe problem of precise registration of the individual impressions arerelated to the use of multiple plates. What is really needed is aprinting system which utilizes a single plate for color applicationwherein only one impression is required to lay down the full colorpattern. While the advantages of full color printing in a simpleimpression has been previously recognized, as indicated by the patcutsto Miller, 3,213,787; Marinier et 211., 680,533; Japanese Patent 36/8,139; and Austrian Patent 51,285; no such system apparently enjoys muchutility in the current printing art.

There are several quite obvious problems attendant to the use of asingle plate which is adapted to print several colors simultaneously andthe difficulties stem, in substance, from one basic problem, i.e., thatof applying the proper color ink to each of the minute projections onthe printing plate and no other projection. Of course, in order tocorrectly accomplish the requisite inking, precise dimensional alignmentof the inking system with the printing plate is necessary. This hasseverely restricted the size of the individual projections and thepossible array patterns which can be employed on the printing plate.

A color printing plate with a plurality of large area projections inwidely-spaced array may, quite naturally, 'be more readily inked than acorresponding plate with much finer projections in close-packed array.On the other hand, for good pattern resolution and high colorsaturation, the dot pattern is preferably held as small as possible, thedeveloped surface area of each projection preferably encompassing anarea of approximately 1-9 x square inches with a separation betweenprojections of perhaps 0.005 inch. With projections of this size, theprob lem of applying the correct color ink to the correct surfaces andto no others is manifest.

For maximum color saturation, the intelligence provided on the printingplate preferably comprises a plurality of minute projections oriented inclose-packed triangular array, an equilateral triangular array havingthe projections interlaced in a direction parallel to the principal axisof the individual unit triangles being preferred. The triangular arrayis capable of giving a higher degree of color saturation than the moreconventional square array, as best illustrated in FIGS. 8, 9 and 10.

FIG. 8 shows a unit triangle 2 of projections 4, 6, 8 in close-packedtriangular array, the individual projections being so spaced as topreclude any overlap of the ink from the dots due to ink spread 10, asdefined by the dashed lines. This spread as indicated in FIG. 7 will begreater or lesser depending upon the ink composition utilized in theprocess, but, more importantly, upon the absorptivity of the paper. Therelationship between the various arrays, and particularly the projectionspacing, is shown in the various drawings, r equalling the radius of theprojection, r indicating the radius of the impression including inkspread. With the s-o-called slick papers common to the magazine fieldthe ink spread will be correspondingly less than that expected withcommon newsprint. In a sense, however, the ink spread is of some valuein the present invention since it permits a somewhat greater spacingbetween adjacent projections than would be the case with the lessabsorptive papers. The amount of ink spread can vary from close to zeroin the case of slick paper to about 40 percent in the case of newsprintand newspaper ink.

The triangular array of FIG. 8 can yield a maximum saturation of 90.7percent, this value being from two (for slick papers) to four (fornewsprint) times as much as the saturation in the loosely-packed arrayof FIG. 9. The square array of FIG. 10 is capable of yielding a maximumof only 59.8 percent. The close-packed triangular array yields asignificant advantage in color printing, wherein the degree of colorsaturation which is achievable heavily influences the fidelity of thecolor reproduction which can be attained.

It will be noted that in the unit cell 12 of the square array of FIG. 10there appears to be a dot missing at the lower right-hand corner. Thisstems from the fact that only three colors are illustrated. In todaysprinting art, this site 14 is sometimes filled with a fourth color,although the fourth color is not necessary to achieve all of the colorhues required in the final reproduction, providing the three colors areproperly selected. Although in the drawings and in the specification,reference is made to red (R), yellow (Y) and blue (B) for the sake ofsimplicity, according to fundamental physics, the proper colors wouldnormally be magenta, yellow and cyan. Some mixture of the three basiccolors maybe used as the fourth color.

Although a combination of the three basic colors may be used, the usualpractice is to occupy the unoccupied site with black ink to reduce theamount of white background showing through the color thereby deceivingthe eye of the viewer and leading to the belief that there is greatercolor saturation than actually exists. This technique is particularlyeffective when black ink is used in this location. The pseudo-saturationthus achieved would then amount to about 78.5 percent, which is stillconsiderably less than that achieved with the triangular array of FIG. 8and is accomplished, generally, only with the addition of a fourthcolor. In any event, the fact that this stratagem is used to gain lessthan a 20 percent addition in saturation is evidence in itself of itsfundamental importance.

In the context used herein, the term color saturation will be seen tohave reference to the percentage of the paper which is covered bycolored ink. The smaller this percentage the greater the backgroundwhite of the paper shows through. As observed by the viewer, thebackground serves to dilute the colors which are perceived, the redsappearing pink, etc. While dilution of the deposited colors by opticalblending with the background of the paper is the method used in theinstant case to achieve the pastel colors and other shading in thefinished reproduction, it is used effectively only in combination withareas of high saturation and color brilliance. And the requisitebrilliance cannot be attained using arrays wherein the background isprominent. In the present invention the area density of the projectionsis selectively varied on the printing plate to provide the different andsometimes subtle degrees of shading required to produce flesh tones, forexample, while retaining high brilliance and color saturation in otherareas as desired.

In each unit triangle on the printing plate, the projections occupyingthe individual apex positions are each inked with a different color,such as red, yellow and blue, as seen in FIG. 4, for example. To adaptthe printing plate for color, some or all of the projections are removedfrom selected areas of the pattern, as indicated at 16 in FIG. 4. Sincethe ink is transferred to the individual projections in such a mannerthat a specific projection receives ink of a single color, eliminationof the surrounding surfaces which normally carry a different color willresult in the printing of only one color in that area of the paper. Andas previously indicated, by varying the projection area density in thatportion of the pattern, the color may be shaded as desired into thepastels.

In a somewhat similar manner, by the selective elimination of one ormore of the projections carrying a given color, various intermediatehues may be provided from the three basic colors. Assuming that red,yellow and blue inks are applied to the projection surfaces forming theapexes of each unit triangle, elimination of the red projection, whileretaining both the yellow and blue, will provide to the viewer anoverall physiological impression of green in the finished print, darkeror lighter shades of green being effected by employing more or less blueand, correspondingly, less or more yellow in a given area. And if thesurface area of the individual dots is small enough, the human eye willnot discern the individual blue and yellow impressions but only theoverall green effect. The overall optical blending efiect, moreover, is

accomplished with no physical mixing of the various inks or overlay ofan ink of one color upon another. The intelligence provided on thesingle printing plate will, accordingly, not only provide the desiredpicture pattern but, also, the appropriate precise coloring thereof.

While any convenient method may be utilized in the fabrication of theprinting plate, that taught by the instant inventor in his copendingapplication Ser. No. 546,996, filed May 2, 1966, is preferred, the blackand white plate of that application being further provided with therequisite color intelligence as hereinbefore discussed. Although in theinstant case, the ink-carrying surface of the projections have beenillustrated and described as dots, for the purposes of this inventionother surface configurations, such as squares, triangles,parallelograms, etc., are contemplated.

The spacing 18 between the individual projections, although preferablyuniform on each printing plate, will nevertheless vary from plate toplate as a function of the ink-paper combination. Accordingly, thespacing utilized for the slick papers Will normally be less than thatsuitable for the more absorptive materials. However, once the spacinghas been correctly established for the given ink-paper combination inquestion, it will be substantially invariant in that operationthereafter. The optimum spacing between projections will be such thatthe ink from one projection, including the spread thereof, will justabut that of the adjacent projections, thereby minimizing effect of thewhite background and, hence, maximizing the color saturation of thepaper.

The general arrangement of a typical printing press assembly adapted tobe used in the practice of the subject invention is illustrated somewhatschematically in FIG. 1. It consists, as shown, of two printing platecylinders 20 and 22 Which are positioned on opposite sides of the paperweb 24, thereby permitting simultaneous printing on both sides of theWeb. Each cylinder'may carry one or more printing plates in the usualmanner, each plate representing a page or impression to be printed onthe paper. As hereinbefore discussed, one or more of the printing platesused may be provided with the appropriate intelligence to effect thesimultaneous printing of a pinrality of colors in the pattern and formrequired in the finished reproduction. Since the printing plates in thisapparatus are to be mounted upon cylindrical rolls 20 and 22, theprinting plates (not shown in this figure) are normally curved toconform to the curvature of the printing plate cylinder and are attachedthereto so that the plates are concentric therewith. Further, therespective projections on the printing plate will be substantiallyidentical as to configuration and height to simplify the alignment andfabrication problems.

The printing plates are inked by three or more sets of ink transferrollers 26, 28, 30 with cooperating inking rollers 32, 34, 36,respectively, the number of inking sets depending upon the number ofcolors to be applied to the printing plate. For full colorreproductions, three ink transfer rollers will normally be used in thepreferred embodiment of the invention. All of the primary colors and theintermediate hues and shades may be provided from these three basiccolors which are referred to herein as red, yellow and blue, although aspreviously discussed, other colors may be advantageously employed toyield the optimum results.

As indicated most clearly in FIG. 2, each of the ink transfer rollers26, for example, is provided with a plurality of ribs 39 on its exteriorsurface, the ribs receiving ink from the inking roller 32 andtransferring it in due course to the appropriate projections 8 on theprinting plate 38. In a preferred arrangement, the ribs comprisecircumferential rings on the ink transfer roller, the ribs being equallyspaced therealong and formed to the same shape and height.

It is essential that the means of transferring the separate ink colorsto the dot projections on the printing plate be such that only red inkis deposited on the red projections, only blue ink on the blueprojections, etc. The projections on the printing plates are arranged,therefore, whereby the red, yellow and blue dots occupy the identicalapex positions in each unit triangle, as illustrated in FIG. 4. Each ofthe projections occupying the corresponding position in each unittriangle is accordingly provided with ink of the same color. Theprojections occupying the corresponding apex positions in each of theunit triangles furthermore lie in spaced parallel rows 40, 42, and theprojections occupying the other apex positions in the unit triangles maybe seen to interlace in a direction parallel to those rows, thisdirection being defined as the principal axis 43 of the unit triangle 2.It will be noted in the embodiments illustrated in the drawings thatthis axis extends vertically of the paper, or, in other words,circumferentially of the printing plate cylinder. This is a preferredorientation as hereinafter dis cussed in detail, but it will be obviousthat other orientations are feasible in the practice of the invention.

The ink transfer rollers are aligned axially so that the ribs providedon the red ink roller are in alignment with the rows of the redprojections, the ribs of the blue ink rollers are aligned with the blueprojections, etc. When three colors are used in this apparatus,therefore, the ribs on each individual roller will be spaced apart by adistance 44 corresponding to three times the spacing between adjacentrows of projections. Furthermore, the respective rollers will be axiallyaligned with the printing plate such that the ribs thereon are axiallydisplaced from those on each other roller by a distance 46 correspondingto the unit spacing between adjacent rows of projections. This is mostclearly illustrated in FIG. 3.

Since the use of a close-packed triangular array with interadjacentprojections is contemplated, it may be seen that the width 48 of therespective rib surfaces on the ink transfer rollers is critical. If thewidth of the ribs is commensurate with the diameter 49 of the individualprojections on the printing plate, such that as a rib rolls over aspecific row of projections, the entire surface of each projection inthat row is entirely covered with ink. Ink will also be transferred tothe outer edges 50 of the projections in the adjacent rows, as seen inFIG. 5. Thus, in this situation, it is impossible to deposit just asingle color of ink on a given dot projection from a continuous rib. Theobvious solution to this problem, and that usually used, is to retreatto the more loosely packed array, such as that shown in FIG. 7, forexample. This, however, is a generally unsatisfactory solution to theproblem and, as discussed extensively, this leads to a serious dilutionof the color in the final reproduction, because of low color saturationof the paper.

In accordance with the present invention, the width 48 of the ribsurface is held less than the spacing 52 between the inner periphery ofalternate rows of projections, and the ink is deposited on eachprojection in the form of a thin stripe 54, as seen in FIG. 4. In otherWords, the entire projection surface is not covered with ink during theinitial transfer process. This allows a considerable measure of controlto be exercised on the subsequent transfer of ink to the paper. Thestripe of ink is squeezed between the projection surface and the paperduring the impression portion of the printing cycle, causing the ink tospread over the entire dot surface. The spread of ink is thus more orless confined to the geometry of the projection surface itself, althoughthere will, of course, be some side spread of ink due to the absorptivenature of the paper, as shown in FIG. 7. By spacing the adjacentprojections such that the ink, including the spread portion on thepaper, deposited by one projection just abuts that deposited by eachadjacent projection, distinct deposits of the individual colors with nodilution results, on the printed page. By appropriate adjustment of theink composition and viscosity, very vivid and faithful reproductions areaccordingly achieved.

Another significant advantage of the interlaced triangular array isworthy of mention at this point. It is, of course, advantageous tomaintain the developed area of each of the unit impressions on the paperof such small magnitude that the individual dots are not discernible tothe naked eye. However, even when this is done in many of the currentmulticolor printing systems and, for that matter in much half-toneprinting, the overall effect on the viewer is often less thansatisfactory. \Vhile the eye is not able to segregate each individualdot as printed, it is, nevertheless, frequently able to discern adistinct linear pattern made up of microscopic impressions laid withoutinterruption in distinct rows, as in FIG. 6. And this is particularlytrue in those instances where the orientation of the rows coincides withthe normal direction of eye scan for the viewer. For this reason, it isa quite common practice to orient the rows at some angle to normalvertical and horizontal directions of scan. In the instant invention, asbest seen in FIGS. 4 and 8, while the various projections are arrangedin distinct rows, the effect of lineation is, to a substantial degree,markedly reduced in most instances and completely eliminated in others,particularly in those areas wherein a plurality of colors are printed.When the complete ink pattern is laid down on the paper, there is notonly no color lineation vertically and horizontally, but none in anydirection.

As previously mentioned, a preferred orientation of the rows ofprojections and, correspondingly the ribs on the ink transfer rollers,is circumferential as shown in the drawings. While not essential, thisorientation is preferred because it permits a precise alignment of theribs with the correct projection rows by means of a single axialadjustment of the ink transfer rollers, thereby eliminating thenecessity for a corresponding rotational adjustment as well. Thisgreatly simplifies the procedures in the press room, and the requisitealignment may be readily achieved by either manual or automaticcontrols.

Another preferred arrangement (not shown) would be to have theprojection rows and roller ribs oriented axially of the respectivecylinders, in which case only a rotational adjustment and alignmentproblem is presented. And, of course, a combination of the two systemsmay be utilized, wherein an axial alignment is required in the case ofsome of the ink transfer rollers and a rotational alignment is requiredin the case of the remaining rollers. In any event, only a singledirection alignment problem is presented at each row.

The other possible orientations, wherein the ribs and rows extendneither circumferentially nor axially of the cylinders but at an anglethereto, while workable in the context of the instant invention, areless preferred techniques, since both an axial and rotationalregistration problem is presented to the press room personnel.

It will be noted that in the system described there is perfectregistration of the separate color patterns in the finished print, thisperfect registration being inherent in the system in the printing plateitself and, accordingly, any stretching, shrinkage or weaving of thepaper during the press run may be expected to exert no influence on theregistration of the colors. Colors properly applied to the printingplate are faithfully reproduced on the paper regardless of changes inthe press room environment. Furthermore, costs as compared to the colorprinting system currently enjoying utility, are much reduced since thepreparation of only a single printing plate is required and the presentalignment problems associated with full color printing are much reduced.And the system described is compatible with the equipment and facilitiescurrently available in the usual newspaper plant.

While the present invention has been described in connection withparticular preferred embodiments and arrangement of parts, variousmodifications, additions and alternative arrangements will be evident tothose skilled in the art within the true spirit and scope of theinvention as set forth in the appended claims.

What is claimed is:

1. Apparatus for printing color reproductions of high resolution, colorfidelity and color saturation in a single impression in a printingpress, comprising:

a printing plate mounting;

a printing plate affixed to the mounting and having the intelligence tobe printed provided thereon in relief, the intelligence comprising aplurality of interadjacent microscopic projections in an overalltriangular array, each of the projections having a discrete surface areafor receiving ink, the projections which occupy the corresponding apexpositions in each of the unit triangles of the array lying in spacedparallel rows;

a plurality of ink transfer members in contact with the printing plateprojections, each of the members having a plurality of spaced ribsthereon oriented parallel to specific rows of projections and inalignment therewith, the surface of each rib being adapted to carry inkand having a width not exceeding the spacing between the inner portionof alternate rows of projections, the spacing between ribs being amultiple of the projection row spacing, the respective ink transfermembers being aligned with each other in the press so that the ribs oneach ink transfer member are displaced from those on each other member;

and means for inking the rib surfaces of the respective ink transfermembers with the desired color.

2. Apparatus for printing color reproductions of high resolution, colorfidelity and color saturation in a single impression in a printingpress, comprising:

a rotatable printing plate cylinder;

a printing plate affixed to the cylinder and having the intelligence tobe printed provided thereon in relief, the intelligence comprising aplurality of microscopic projections in triangular array, each of theprojections having a discrete surface area for receiving ink, therespective projections which form the apexes of the individual unittriangles being interlaced in a direction parallel to the principal axisof the triangle, the projections which occupy the corresponding apexpositions in each of the unit triangles lying in spaced parallel rows;

a plurality of ink transfer rollers rotatable in coordination with theprinting plate cylinder and in contact with the printing plateprojections, each of the rollers having a plurality of spaced ribsthereon oriented parallel to the specific rows of projections and inalignment therewith, the surface of each rib being adapted to carry inkand having a width not exceeding the spacing between the inner edges ofalternate rows of projections, the spacing of the similarlyoriented ribscorresponding to that between adjacent rows of projections times thenumber of different inks to be applied to the printing plate in thatdirection, the respective rollers being aligned in the press so that theribs thereon at contact with the printing plate are displaced from thoseon each other roller by a distance corresponding to the spacing betweenadjacent rows of projections;

and means for inking the rib surfaces of the respective rollers with thedesired color.

3. Apparatus as set forth in claim 2 having printing plate intelligencewherein:

selected projections on the printing plate are eliminated to provide therequisite hues in the finished reproduction; and

the area density of the projections is selectively varied over theprinting plate area to provide different degrees of shading, brillianceand color saturation in the finished reproduction.

4. Apparatus as set forth in claim 3 wherein:

the respective projections on the printing plate are substantiallyidentical as to configuration and height; and

the printing plate is curved to conform to the curvature of the printingplate cylinder and is attached concentrically thereto.

5. Apparatus as set forth in claim 4 wherein:

the respective rows of projections extend circumferentially of theprinting plate; and

the ribs on the ink transfer rollers are oriented circum-' ferentially.

6. Apparatus as set forth in claim 4 wherein:

the respective rows of projections extend axially of the printing plate,and the ribs on the ink transfer rollers are oriented axially.

7. Apparatus as set forth in claim 3 wherein:

three ink transfer rollers are provided, the first roller being inkedwith a first color, the second roller being inked with a second color,and the third roller being inked with a third color.

8. Apparatus as set forth in claim 7 wherein:

the first, second and third colors are selected to provide the entirecolor spectrum desired in the finished reproduction.

9. Apparatus as set forth in claim 7 wherein:

the first, second and third inks are colored cyan, magenta and yellow,respectively.

10. Apparatus as set forth in claim 2 wherein:

the spacing between adjacent projection locations is selected so thatthe ink pattern deposited by one projection just abuts that deposited byan adjacent projection.

11. Apparatus as set forth in claim 10 wherein:

the developed printing surface area of the individual projections is 1-9x 10' square inches.

12. Apparatus for printing full color reproductions of high resolution,color fidelity and color saturation in a single impression in a rotaryprinting press, comprising:

a rotatable printing plate cylinder;

a conforming printing plate aflixed to the cylinder and having theintelligence to be printed provided thereon in relief, the intelligencecomprising a plurality of microscopic projection in overall triangulararray, each of the projections having a discrete surface area forreceiving ink, the respecitve projections which occupy the apexes of theindividual unit triangles being interlaced circumferentially, theprojections which occupy the corresponding apex positions in each unittriangle lying in spaced parallel rows extending circumferentially ofthe printing plate, each projection row lying parallel to each otherrow;

three ink transfer rollers rotatable in coordination with the printingplate cylinder and in contact with the printing plate projections, eachroller transferring an ink of a different color and having a pluralityof axially spaced circumferential ribs thereon, the surface of the ribshaving a width less than the spacing between inner portions of alternaterows of projections, the spacing between ribs corresponding to threetimes the projection row spacing, the respective rollers being axiallypositioned in the press so that the ribs on each roller are axiallydisplaced from those on each other roller by a distance corresponding tothe spacing between adjacent rows of projections;

and means for inking the rib surfaces of each of the respective rollerswith ink of a different color.

13. Apparatus as set forth in claim 12 wherein:

the respective projections on the printing plate are substantiallyidentical as to configuration and height.

14. The method of printing color reproductions in a single impressionwhich comprises the steps of providing a printing plate having theintelligence to be printed provided thereon in relief, the intelligencecomprising a plurality of interadjacent microscopic projections inoverall triangular array, the projections occupying the correspondingapex positions in each unit triangle being oriented in spaced parallelrows;

depositing a thin stripe of ink on the respective rows of projections ina direction corresponding to the projection row orientation;

and impressing the printing plate on the material to be printed withsufficient force to cause the ink to spread over the entire surface ofeach projection.

15. The method of printing full color reproductions in a singleimpression which comprises the steps of:

providing a printing plate having the intelligence to be printedprovided thereon in relief, the intelligence comprising a plurality ofinteradjacent microscopic projections in overall triangular array, theprojections occupying the corresponding apex positions in each unittriangle being oriented in spaced parallel rows;

depositing a thin stripe of ink on the respective rows of projections ina direction corresponding to the projection row orientation, adjacentrows of projections being ink-ed with a first, second and third color,repsectively;

and impressing the printing plate on the material to be printed withsufficient force to cause the ink to spread over the entire surface ofeach projection.

16. The method of claim 15 wherein:

the first, second and third colors are magenta, yellow and cyan.

17 The method of claim 15 wherein:

the printing plate is installed in a rotary press; and

the projection rows extend circu-mferentially.

References Cited US. Cl. X.R.

1. APPARATUS FOR PRINTING REPRODUCTIONS OF HIGH RESOLUTION, COLORFIDELITY AND COLOR SATURATION IN A SINGLE IMPRESSION IN A PRINTINGPRESS, COMPRISING: A PRINTING PLATE MOUNTING; A PRINTING PLATE AFFIXEDTO THE MOUNTING AND HAVING THE INTELLIGENCE TO BE PRINTED PROVIDEDTHEREON IN RELIEF, THE INTELLIGENCE COMPRISING A PLURALITY OFINTERADJACENT MICROSCOPIC PROJECTIONS IN AN OVERALL TRIANGULAR ARRAY,EACH OF THE PROJECTIONS HAVING A DISCRETE SURFACE AREA FOR RECEIVINGINK, THE PROJECTIONS WHICH OCCUPY THE CORRESPONDING APEX POSITIONS INEACH OF THE UNIT TRIANGLES OF THE ARRAY LYING IN SPACED PARALLEL ROWS; APLURALITY OF INK TRANSFER MEMBERS IN CONTACT WITH THE PRINTING PLATEPROJECTIONS, EACH OF THE MEMBERS HAVING A PURALITY OF SPACED RIBSTHEREON ORIENTED PARALLEL TO SPECIFIC ROWS OF PROJECTIONS AND INALIGNMENT THEREWITH, THE SURFACE OF EACH RIB BEING ADAPTED TO CARRY INKAND HAVING A WIDTH NOT EXCEEDING THE SPACING BETWEEN THE INNER PORTIONOF ALTERNATE ROWS OF PROJECTIONS, THE SPACING BETWEEN RIBS BEING AMULTIPLE OF THE PROJECTION ROW SPACING, THE RESPECTIVE INK TRANSFERMEMBERS BEING ALIGNED WITH EACH OTHER IN THE PRESS SO THAT THE RIBS ONEACH INK TRANSFER MEMBER ARE DISPLACED FROM THOSE ON EACH OTHER MEMBER;AND MEANS FOR INKING THE RIB SURFACES OF THE RESPECTIVE INK TRANSFERMEMBERS WITH THE DESIRED COLOR.